AN APPARATUS AND METHOD TO MEASURE A PARAMETER OF A FLOW OF MULTIPLE PHASES
TECHNICAL FIELD This invention relates to an apparatus for measuring a parameter of a process flow passing inside a tube, and more particularly to a flow measuring apparatus having ultrasonic detectors and an array of detectors based on stresses and for processing the data signals thereof to provide a result indicative of the speed of sound propagation through the process flow and / or a flow parameter, of the process flow passing through a tube. ANTECEDENT TECHNIQUE In fields involving flowing fluids for industrial applications, such as suspensions, liquids, chemicals, paper, pulp, oil, gas, medicine, food, mining, minerals, and refining vapors and gases, it is sometimes beneficial. Know certain characteristics of the flowing fluids. For example, in the oil industry in which billions of dollars of crude oil are physically measured every day on the way from the wells to the refineries, the volumetric flow is a critical measurement in the control and optimization of the processes. Unfortunately, however, large quantities of hydrocarbons tend to be present in crude oil and as such, during transportation from wellheads and refineries crude oil has a propensity to 'release gases' during transport, which results in unknown small levels of entrained gases that are present in the physical measurement locations. This is undesirable for at least two (2) reasons. First, because the effect of entrained gases on most liquid volumetric technologies results in an excessive reporting of the flow rate of the liquid component by an amount equal to the volume of the entrained gases, the measured volumetric flow rate is typically inaccurate. In fact, standards have been imposed for volumetric flow. Unfortunately, however, although most standards for the physical volumetric flow of liquids require that the liquid be completely devoid of gases, a problem arises when it becomes impractical to ensure that the liquid stream in question is actually devoid of gases . This is because, although the level of the gas volumetric fraction (GVF) is typically less than 1%, this is often the primary source of errors in physical measurements. Second, because the complete physical separation of the gas and liquid phases can not be ensured, the determination of the liquid volume is also typically inaccurate resulting in an inaccurate value of the water cut. Therefore, it is reasonable to expect that the more features about the flowing fluid become known, the better opportunities will be to effectively measure, control and optimize the processing of the flowing fluid. The accuracy of the measurement of oil production is typically limited to three restrictions. One constraint is the inability to ensure complete separation of gas and liquid flows. This restriction results in an inaccurate determination of the volume of the liquid, an inaccurate determination of the gas volume, and an inaccurate determination of the water cut. The second restriction is the relatively low number of flow measurements. This is not only due to the installation and maintenance requirements for each measuring device but also to the effect that each measuring device has on the flow of the fluid, such as the associated pressure drop. In itself, increasing the number of measurement points causes a corresponding increase in the associated total pressure drop as well as an increase in the number and cost of installation and maintenance requirements. The reason is the maintenance requirements, the installation requirements, and the pressure drop at the point with any increase in the measurement points. The third restriction is the very low number of measurement points of the water cut. This low number is due to the reliability of the water cut measurement devices and the calibration requirements of the meters. Thus, it would be advantageous, particularly in wells and production fields, to have a non-intrusive, reliable clamping or clamping apparatus capable of measuring the parameters of an aerated multi-phase fluid flow, such as the volumetric flow rate of the liquid of the process stream, the volume fraction of the gas (or vacuum) of the stream, the water cutoff of the stream, and the volumetric flow rate of each of the stream phases. The present invention provides such an apparatus. BRIEF DESCRIPTION OF THE INVENTION An apparatus is provided for determining a characteristic of an aerated fluid flowing within a pipe, wherein the device includes at least a first detection device. The at least one first detection device is associated with the pipe, such that the at least one first detection device detects a low frequency component of the aerated fluid stream and generates the data of the first detector in response to the low frequency component. of the aerated fluid. Additionally, at least one second detection device is provided, wherein the at least one second detection device is associated with the pipe such that the at least one second detection device detects a high frequency component of the aerated fluid stream, in where the data of the second detector is generated in response to the high frequency component of the aerated fluid. In addition, a processing device is provided, wherein the processing device communicates with the at least one first detection device and the at least one second detection device for receiving and processing the data of the first detector and the data of the second detector. to generate the fluid data, in response to a characteristic of aerated fluid flow. A method for determining a characteristic of a fluid flowing within a pipeline is provided, wherein the method includes generating Sound Velocity data in response to the speed of sound within at least a portion of the fluid for at least one of a first frequency and a second frequency, detect the convection velocity of the pressure fields created by the fluid and generate the convection data in response to the convection velocity of the pressure fields. Additionally, the method includes processing the Sound Velocity data and the convection data to determine the fluid characteristic. An apparatus for determining the value of the water cut of a multi-phase fluid flowing within a tube is provided, wherein the device includes a transmission device configured to introduce a high frequency acoustic signal into the fluid, a device for reception, wherein the receiving device is configured to receive the high frequency acoustic signal after the high frequency acoustic signal has passed through at least a portion of the fluid, wherein at least one of the transmission device and the receiving device generates the detector data in response to the received high frequency acoustic signal and a processing device, wherein the processing device communicates with at least one of the transmission device and the receiving device to receive and process the detector data to determine the value of the water cut of the fluid. A method is provided to determine the value of the water cut of a fluid flowing through a tube, wherein the method includes introducing into the fluid an acoustic wave having a predetermined frequency, after the acoustic wave has passed through at least a portion of the fluid, receiving the acoustic wave and generating the detector data in response, at least in part, to the received acoustic wave and processing the detector data to determine the value of the fluid water cutoff. The foregoing and other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of the exemplary embodiments thereof. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of a flow measuring apparatus having an arrangement of stress-based detectors for measuring the parameters of a multiple phase flow according to the present invention. Fig. 2 is a graph of the measured sound velocity, normalized to the speed of sound of the liquid over a range of frequencies according to the present invention. Fig. 3 is a graph of the measured sound velocity, normalized to the speed of sound of the liquid as a function of the fraction of the gas volume according to the present invention. Fig. 4 is a schematic diagram of a flow measurement apparatus of Fig. 1 having an arrangement of stress-based detectors and an array of ultrasonic detectors for measuring the parameters of a multiple phase flow.
Fig. 5 is a cross-sectional view of a tube having a turbulent fluid flow or a mixture flowing therein, the flow having coherent structures therein, i.e. acoustic waves and spiral perturbations, according to the present invention. Figs. 6 and 7 are block diagrams of the GVF Logic according to the present invention. FIG. 8 is a schematic diagram of a sound velocity logic (SOS) of an array processor of a flow measurement apparatus according to the present invention. Fig. 9 is a graph KÜ of data processed from an apparatus embodying the present invention, which illustrates the slopes of a pair of acoustic crests, according to the present invention. Fig. 10 is a graph of the mixing sound velocity as a function of the fraction of the gas volume over a range of process pressures, according to the present invention. Fig. 11 is a schematic diagram of a flow logic of an array processor of a flow measurement apparatus according to the present invention. Fig. 12 is a graph KQ of the data processed from an apparatus embodying the present invention, which illustrates the slope of the convection peak, and a graph of the optimization function of the convection peak, according to the present invention. Fig. 13 is a graph of the sound velocity of the liquid as a function of the volume fraction of the water in the multi-phase flow according to the present invention. FIG. 14 is a block diagram of another embodiment of a flow measurement apparatus having an array of stress-based detectors and ultrasonic sensors for measuring the parameters of a multi-phase flow according to the present invention. Fig. 15 is a schematic diagram of a flow measurement apparatus of Fig. 14 having an array of stress-based detectors and an array of ultrasonic detectors for measuring the parameters of a multiple phase flow. BEST MODE FOR CARRYING OUT THE INVENTION Fig. 1 illustrates a block diagram of a flow measurement device 100 for measuring a parameter of a multi-phase flow 102 that passes through a tube 104. Multiple phase flow or mixture 102 includes any mixture having any combination of a gaseous, liquid or solid phase. Although the present invention is particularly useful for measuring multiple phase flows 102, the apparatus 100 can also measure a parameter of a one phase flow. As discussed above, apparatus 100 incorporating the present invention is useful for measuring a multi-phase flow 102 comprising oil, water and gas. The description of the present invention will assume that the mixture is a combination of petroleum, water and gas, however, the invention contemplates that any one-phase or multi-phase flow 102 can be measured. As shown in Fig. 1, the apparatus 100 functions as a meter 106 of the volume fraction of the gas (or vacuum), an ultrasonic flow meter 108, and an ultrasonic meter 110 of the water cut. The gas volume fraction meter (GVF) 106 provides a result indicative of the gas volume fraction of the mixture 102 by measuring the velocity of sound propagation at low frequencies axially through the flow 102 in the tube 104. The ultrasonic flow meter 108 provides a plurality of high frequency acoustic signals through the flow 102 to provide output signals indicative of pressure disturbances (e.g., vortical disturbances) or other disturbances or other characteristics conveyed by convection or they propagate with the flow 102 in front of the ultrasonic detectors, which will be described in more detail below. The ultrasonic water cut meter 110 measures the speed of sound of a high frequency signal propagating through the flow 102 to provide an output signal indicative of the sound velocity of the liquid component of the flow 102, which is indicative of the water cut of the mixture 102. The water cut is the phase fraction or the percentage of the water in the liquid portion of the flow 102. One can appreciate that the combination of the GVF meter 106, the meter 108 of flow and the water cut meter 110 provides sufficient information to fully characterize the multi-phase fluid 102 that passes through the tube 104. Specifically, the apparatus 100 is capable of measuring at least the flow rate, the volumetric flow rate , the composition of the flow (for example, the phase fraction of each phase of the fluid), the water cut, the volumetric flow rate of each phase of the mixture 102, the volumetric fraction of the gas (vacuum) of the flow, the velocity of the sound of the mixture 102 and the sound velocity of the liquid component of the flow 102. One can appreciate that these measured parameters are particularly important in oil production applications. An important aspect of the present invention is the recognition that there exists a dependence for the bubbling fluids of the frequency at the velocity of sound propagation through the flow 102 of the fluid. The resonance of the bubbles determines the frequency of transmission. Fig. 2 illustrates the frequency dependence of the speed of sound in bubbling fluids. As shown, at low frequencies below the resonance frequency of the bubbles (approximately 100 Hz to 1000 Hz), the speed of sound propagation through the fluid 102 is dramatically influenced by the entrained gases. On the other hand, at high frequencies above the resonance frequency of the bubbles (approximately 1 MHz and more), the gas entrained in the flow 102 of the fluid does not have a significant impact on the velocity of sound propagation through the component. flow liquid 102. Recognizing this phenomenon, the apparatus 100 incorporating the present invention provides a meter (i.e., a GVF meter 106) for measuring the speed of sound at low frequencies below the resonance frequency of the bubbles, and another meter (i.e., an ultrasound meter 108 of the water cut) for measuring the speed of sound at high frequencies above the resonance frequency of the bubbles. As will be described in more detail hereafter, the measured sound velocity at the lower frequencies (i.e. sub-resonance frequencies) is indicative of the speed of sound of the mixture 102, while the velocity of the measured sound at the higher frequencies (e.g., super-resonance frequencies) is indicative of the sound velocity of the liquid component of the mixture 102. Knowing the sound velocity of the mixture 102 allows the volume fraction to be determined of gas (and vacuum) of flow 102 (or mixture). Furthermore, knowing the speed of sound of the liquid component of the mixture 102 allows the water cut to be determined. This processing will be described in more detail hereinafter. Also, knowing the volume fraction of the gas (or the vacuum fraction) and the water cutoff, the phase fraction and the volumetric flow rate of the fluid flow 102 can be determined, as will be described in greater detail below. Tests were carried out using a vertical tube filled with a fluid, where bubbles were injected into the fluid at the bottom of the tube. The sound velocity was measured at super-resonance frequencies and sub-resonance frequencies using an ultrasonic detector and a GVF meter. The data is provided in Fig. 3, which illustrates the phenomenon described above that the sound velocity of the liquid component of the mixture 102 (e.g., the super-resonance SOS) is not affected by the entrained gas, while the measured sound velocity of the mixture 102 (for example, the sub-resonance SOS) is affected by the entrained gas. Fig. 3 illustrates the effects of the sound velocity of the mixtures or bubbling flows. Specifically, the measured sound velocity normalized by the speed of sound of the liquid is plotted as a function of the volume fraction of the reference gas. Line A shows the measured, normalized super-resonance sound velocity as a function of the referenced GVF. As discussed below, the speed of sound measured at the highest frequencies (super-resonance) is not affected by the entrained gas and is indicative of the sound velocity of the liquid of the mixture 102 regardless of the amount of entrained gas . Line B shows the measured, normalized sub-resonance sound velocity as a function of the referenced GVF. As discussed below, the measured sound velocity at the lowest (sub-resonant) frequencies is affected by the gas entrained by a known or determinable relationship, and thus allows the determination of the volume fraction of gas (or vacuum) of the flow or mixture 102 of multiple phases. Line C shows the theoretical normalized sub-resonance sound velocity of mixture 102 as a function of the referenced GVF, according to the Woods equation. As shown, the measured sub-resonance sound velocity correlates with the theoretical determination of the sub-resonance sound velocity. Fig. 4 illustrates a schematic diagram of the flow measurement apparatus 100 of Fig. 1 including a sensing device 112 (detector head) mounted on the tube 104 and a processing unit or processor
(transmitter) 114 of the arrangement. The apparatus 100, according to the present invention, can determine the speed at which the sound propagates (i.e., the acoustic waves 90 in Fig. 5) through the flow 102 of the fluid within the tube 104, to measure the particular characteristics of the fluids 102. To simplify the explanation of the present invention, the flow 102 propagating through the tube 104 will be referred to as a process flow 102 with the understanding that the fluid or process flow 102 can be a single-phase or multi-phase flow, as described below. The detection device 112 comprises an array of detectors based on strain strains or pressure detectors 116-122 for measuring the unstable pressures produced by acoustic pressure disturbances (e.g., acoustic waves 90) within the tube 104, so as to determining the velocity of the sound propagating through the flow 102. The detection device 112 further includes any array of ultrasonic detectors 124-130, each of which having a transmitter 131 and a receiver 132, also for measuring a flow parameter 102. The detectors, 116-122, of pressure and the ultrasonic detectors 124-130 are shown intertwined, however, one should appreciate that each respective detector arrangement may be partially interlaced or not interlaced in any way, without departing of the scope of the present invention. It is also contemplated that the GVF meter 106 and the ultrasonic flow meter 108 may be two distinct units arranged adjacent to each other in the tube 104. The pressure signals P, (t) -PN (t) and the ultrasonic signals S, (t) -SN (t) are provided to the processing unit 114, which digitizes the signals and calculates the appropriate flow parameter (s). Although a cable is shown to electronically connect the detection device 112 to the processing unit 114, any method and / or device suitable for the desired end purpose can be used to communicate the detection device 112 with the processing unit 114. The analog pressure detector signals P, (t) -PN (t) are typically 4-20 mA current loop signals.
The array of detectors, 116-122, of pressure comprises an array of at least two pressure sensors, 116, 118, axially spaced apart along an outer surface 134 of the tube 104, which have the process flow 102 propagating within the same. The pressure detectors 116-122 may be secured or mounted generally removably to the tube 104 by means of any releasable fastening device, such as magnetic fasteners, bolts, screws and / or clamps. Alternatively, the detectors may be permanently fixed to, or integrated (e.g., embedded) with the tube 104. The array of detectors of the detection device 112 may include any number of detectors, 116-122 of pressure greater than two detectors, such like three, four, eight, sixteen or N number of detectors between two and twenty-four detectors. In general, the accuracy of the measurement improves when the number of detectors in the array increases. The degree of accuracy provided by the greater number of detectors is compensated by the increase in complexity and the calculation time of the desired output parameter of flow 102. Therefore, the number of detectors used is dependent on at least the degree of accuracy desired and the desired update rate of the output parameter provided by the apparatus 100. The pressure sensors 116-122 measure the unstable pressures produced by the acoustic waves propagating through the flow 102 within the tube 104, which is indicative of the SOS propagating through the flow 102 of the fluid in the tube 104. The output signals (P, (t) -PN (t)) of the detectors, 116-122, of pressure are provided to an amplifier 136 of signals that amplifies the signals generated by the detectors, 116-122, pressure. The processing unit 114 processes the pressure measurement data P, (t) -PN (t) and determines the parameters and desired characteristics of the flow 102, as described below. The apparatus 100 also contemplates providing one or more acoustic sources 138 to allow measurement of the velocity of sound propagation through the flow 102 for cases of acoustically silent flow 102. The acoustic source (s) 138 may be devices that tap or vibrate on the wall of the tube 104, for example. The acoustic sources 138 may be disposed at the end of the inlet or the discharge end of the array of detectors, 116-122, or at both ends, as shown. It should be appreciated that in most cases the acoustic sources 138 are not necessary and that the apparatus 110 passively detects the acoustic crests provided in the flow 102, as will be described in more detail below. Passive noise includes noise generated by pumps, valves, motors, and turbulent mixture 102 itself. In general, the processing unit 114 measures the unstable pressures created by the acoustic disturbances propagating through the flow 102 to determine the speed of sound (SOS) propagating through the flow 102. Knowing the pressure y / or the temperature of the flow 102 and the sound velocity of the disturbances or acoustic waves, as shown in Fig. 6 and Fig. 7, the processing unit 114 can determine the volumetric flow of the fluid 102, the consistency or the composition of the fluid 102, the Match number of the fluid 102, the average size of the particles flowing through the fluid 102, the air / mass ratio of the fluid 102, and / or the percentage of air entrained within the mixture 102, such as that described in US Patent Application No. 10 / 349,716 (CiDRA Registration No.: CC-0579), filed on January 23,
2003, US Patent Application No. 10 / 376,427 (Non-Registry of CiDRA: CC-0596), filed on February 26, 2003, US Patent No. 10 / 762,410 (Non-Registry of CiDRA: CC-0703) ) presented on January 21 of
2004, all of which are incorporated here for reference. As shown in Fig. 4, an apparatus 100 incorporating the present invention has an array of at least two pressure-based detectors, 116, 118, located at two locations x1 (x2, axially along of the tube 104 to detect stochastic signals propagating between the detectors 116, 118, within the tube 104 in their respective locations Each detector 116, 118 provides a signal indicating an unstable pressure at the location of each detector, 116, 118, at each instant in a series of sampling instants.It should be appreciated that the arrangement of detectors may include more than two pressure detectors, 116, 118, as represented by the detectors, 120, 122, of pressure in the locations x3, xN The pressure generated by the acoustic waves 90 (see Fig. 5) can be measured through pressure-based detectors and / or detectors 116-122. The detectors 116-122. of pressure provide signals analogs that vary with time PiJ t), P2 (t), P3 (t), PN (t) to unit 14 of signal processing. As shown in Fig. 8, the SOS Logic 140 of the Mix includes a data acquisition unit 142 that digitizes the pressure signals P, (t) - PN (t) associated with the acoustic probes 90 that propagate through the tube 104. An FFT logic 144 calculates the Fourier transform of the digitized input signals based on the time P, (t) -PN (t), and provides signals in the complex frequency domain (or based on frequency) P1 (?), P2 (?), P3 (?), PN (?) indicative of the frequency content of the input signals. A data accumulator 146 accumulates the signals P, (t) -PN (t) of the detectors, 116-122, and provides the accumulated data through a sampling interval to a processor 148 of the array, which performs a spatial-temporal (two-dimensional) transformation of the detector data, from the domain x (t) to the domain? - ?, and then calculate the power in the plane? - ?, as represented by a graph of? - ?, similar to that provided by the processor of the convection array shown in Fig. 11. To calculate the power in the plane? - ?, as represented by a graph of? -? (see Fig. 9) either of the signals or differentiated signals, the processor 148 of the array determines the wavelength and as such the (spatial) number of waves k, and also the (temporal) frequency and itself, the angular frequency?, of several spectral components of the stochastic parameter. There are several algorithms available in the public domain to carry out the spatial / temporal decomposition of the arrangement of pressure detectors 116-122.
Specifically, the processor 148 of the array uses the standards called beamforming algorithm, array processing, or adaptive array processing, that is, algorithms to process the signals of the detectors using various delays or weighting to create the proper phase relationships. between the signals provided by the different detectors thereby creating a phasing array functionality. In other words, the algorithms of beamforming or processing by arrangement transform the signals in the time domain of the array of detectors to their spatial or temporal frequency components, that is, to a set of wave numbers given by k = 2p /? where ? is the wavelength of a spectral component, and the corresponding angular frequencies given by? = 2pv. One such technique for determining the velocity of sound propagation through flow 102 involves using techniques processing by arrangements to define the acoustic crests in the plane k-? as shown in Fig. 9. The slope of the acoustic ridges is indicative of the velocity of sound propagation through flow 102. The speed of sound (SOS) is determined by applying sonar array processing techniques to determine the speed of sound propagation. speed at which the one-dimensional acoustic waves 90 propagate in front of the axial array of unstable pressure measurements distributed along the tube 104. The apparatus 100 of the present invention measures the speed of sound (SOS) of one-dimensional sound waves 90 (see Fig. 5) which propagate through the mixture 102 to determine the volume fraction of the gas in the mixture 102. It is known that the sound propagates through various media at various speeds in fields such as fields of SONAR and RADAR. The velocity of sound propagation through the tube 104 and the flow 102 can be determined using a number of known techniques, such as those published in U.S. Patent Application Serial Number 09 / 344,094, filed June 25, 1999, now US 6,354,147; U.S. Patent Application Serial Number 10 / 795,111, filed March 4, 2004; U.S. Patent Application Serial Number 09 / 997,221, filed November 28, 2001, now US 6,587,798; US Patent Application Serial Number 10 / 007,749, filed November 7, 2001, and US Patent Application Serial Number 10 / 762,410, filed January 21, 2004, each of which is incorporated here as a reference In the case of suitable acoustic waves 90 that occur in both axial directions, the power in the K-? shown in the graph of Fig. 9 thus determined will exhibit a structure that is called a ridge, 150, 152, acoustic both in the left and right plane of the graph, wherein one of the acoustic ridges 150 is indicative of the speed of the sound traveling in an axial direction and the other acoustic crest 152 which is indicative of the speed of sound traveling in the other axial direction. The crests 150, 152, acoustics represent the concentration of a stochastic parameter that propagates through the flow 102 and constitute a mathematical manifestation of the relationship between the spatial variations and the temporal variations described above. Such a graph will indicate that a trend for the k-? appears more or less along a line, 150, 152, with some slope, the slope that indicates the speed of sound. The power in the plane k-? thus determined is then provided to an acoustic peak identifier 154, which uses one or more characteristic extraction methods to determine the location and orientation (slope) of any acoustic crest, 150, 152, present in the k- plane? left or right. An analyzer 156 determines the sound velocity of the mixture 102 using the slope of one of the two crests 150, 152, acoustically or by averaging the slopes of the acoustic crests 150, 152.
As shown in Figs. 1 and 4, the GVF logic provides output signals indicative of the volume fraction of gas or vacuum of the mixture 102 in response to the measured sound velocity of the mixture 102. For example, to determine the volume fraction of gas (or the phase fraction), the GVF logic assumes an almost isothermal condition for the flow 102. In itself, the volume fraction of the gas or the vacuum fraction are related to the speed of sound by means of the following equation quadratic: Ax2 + Bx + c = 0 where x is the speed of sound, A = l + rg / rl * (Kef / P-1) -Kef / P, B = Kef / P-2 + rg / rl;; Rg = gas density, rl = liquid density, Kef = effective K (liquid module and tube wall), P = pressure, and ameas = measured sound velocity. Effectively Fraction of Gas Volume (GVF) = (-B + sqrt (BA2-4 * A * C)) / (2 * A).
Alternatively, the sound velocity of a mixture 102 can be related to the volumetric fraction of phase (fi) of the components and the velocity of sound (a) and the densities (p) of the component through the Wood equation. 1 N f N 2 = S "yd? Nd? P mixture = S Pi, Pmezcl to mixture" < = • Pfii i = \ The one-dimensional compression waves propagating inside the mixture 102 contained within the tube 104 exert a unstable internal pressure load on the tube 104. The degree to which the tube 104 is displaced as a result of the unstable pressure load influences the propagation velocity of the compression waves.The ratio between the infinite domain sound velocity and the density of mixture 102, modulus (E), thickness (t), and radius (R) of a cylindrical duct backed to the vacuum and the effective propagation velocity (aef) for dimensional compression can be given by the following expression:
The mixing rule essentially states that the compressibility of a mixture (l / (pa2)) is the volumetrically weighted average of the compressibility of the components. For gas / liquid mixtures 102 at the pressures and temperatures typical of the pulp and paper industry, the compressibility of the gas phase is orders of magnitude greater than that of the liquid phase. Therefore, the compressibility of the gas phase and the density of the liquid phase mainly determine the sound velocity of the mixture, and as such, it is necessary to have a good estimate of the process pressure to interpret the sound velocity of the mixture in terms of the volumetric fraction of the entrained gas. The effect of the process pressure on the relationship between the speed of sound and the volume fraction of entrained air is shown in Fig. 10. Some or all of the functions within the processing unit 114 can be implemented in programs (using a microprocessor or computers) and / or an unalterable software, or can be implemented using analog and / or digital physical components, having sufficient memory, interfaces, and the ability to perform the functions described herein. As shown in Fig. 4, the measuring apparatus 100 includes a detection device 112 comprising an array of units, 124-130, ultrasonic detectors. Each unit, 124-1340, detector comprises a pair of ultrasonic detectors, 131, 132, one of which functions as a transmitter (Tx) 131 and the other as a receiver (Rx) 132. Units, 124-130, detectors they separate axially along the external surface 134 of the tube 104 having a process flow 102 propagating therein. The pair of detectors, 131, 132, are diametrically disposed in the tube 104 at predetermined locations along the tube 104, to provide a transmission configuration from one side to the other, such that the detectors, 131, 132, transmit and receiving ultrasonic signals propagating through the fluid 102 substantially orthogonal to the direction of fluid flow 102 within the tube 104. The ultrasonic measurement portion of the present invention is similar to that shown in the U.S. Provisional Application No. 10/756, 977 (Attorney's Record No. CC-0700) filed on January 13, 2004, which is incorporated herein by reference. As shown in Fig. 1, each pair of ultrasonic detectors 131, 132 measures a transit time (i.e., the travel time (TOF), or phase modulation) of an ultrasonic signal that propagates to through the fluid 102 from the transmission detector 131 to the reception detector 132. The measurement or variation of the transit time is indicative of the coherent properties propagating by convection with the flow 102 within the tube 104 (eg, vortical disturbances, irregularities within the flow 104, temperature variations, bubbles , particles, pressure disturbances), which are indicative of the speed of the process flow 102. The detectors, 124-130, ultrasonic can operate at any frequency, however, it has been found that the higher frequency detectors are more suitable for fluids of a phase while the lower frequency detectors are more suitable for fluids of multiple phases. The optimal frequency of the detectors, 124-130, ultrasonic depends on the size or type of the particles or the substance that propagates with the flow 102. For example, the larger the bubbles in an aerated fluid, the lower the frequency of the ultrasonic signal. Examples of frequencies used for a flow meter incorporating the present invention are 1 MHz and 5 MHz. The ultrasonic detectors 124-130 may also provide a pulse, chirp, or continuous signal through the flow 102 of the fluid. An example of the detectors, 131, 132, which can be used are of Model no. 113-241-591, manufactured by Krautkramer. An ultrasonic signal processor 162 triggers the detectors 131 in response to a trigger signal from the transmitter 114 and receives the ultrasonic output signals S, (t) -SN (t) from the detectors 132. The ultrasonic signal processor 162 processes the signals. data from each of the units, 124-130, detectors to provide a signal
T, (t) - analogue or digital output TN (t) indicative of the travel time or the transit time of the ultrasonic signal through the fluid 102. The ultrasonic signal processor 162 provides an output signal indicative of the amplitude (or attenuation) of the ultrasonic signals. One such signal processor is the model no. USPC 2100 manufactured by Krautkramer Ultrasonic Systems. Measuring the amplitude of the ultrasonic signal is particularly useful and works best to measure the velocity of a fluid 102 that includes a substance in the flow 102 (e.g., a fluid or multi-phase suspension). The output signals (T, (t) -TN (t)) of the ultrasonic signal processor 102 are provided to the processor 114, which processes the transit time or the modulation measurement data to determine the volumetric flow rate. Transit time or travel time measurements are defined by the time it takes for an ultrasonic signal to propagate from the transmission detector 131 to the detector
132 of respective reception, through the wall of the tube 104 and the fluid 102. The effect of the vortical disturbances
(and / or other irregularities within the fluid 102) over this transit time of the ultrasonic signal is to retard or accelerate the transit time. Therefore, each unit, 124-130, detector provides a respective output signal T, (t) -TN (t) indicative of the variations in the transit time of the ultrasonic signals propagating orthogonally to the fluid direction 102. The measurements are derived by interpreting the property and / or the coherent convection characteristic within the process pipe 104, using at least two units, 124, 126, detectors. The detectors, 124-126, ultrasonic can be "soaked" or secured on the external surface 134 of the tube 104 (for example, contact or non-contact detectors). In one example, the flow meter 100 measures the volumetric flow rate by determining the velocity of the vortical disturbances or "swirls" 164 (see FIG. 5) that propagate with the flow 102 using the array of detectors, 124-130, ultrasonic . The flow meter 100 measures the velocities associated with the unstable flow fields created by the vortical perturbations or "swirls" 164, in and other irregularities, to determine the flow velocity 102. The units, 124-130, ultrasonic detectors measure the time T, (t) -TN (t) of transmission of the respective ultrasonic signals between each respective pair of detectors, 131, 132, which varies due to vortical perturbations when these disturbances are conveyed by convection within flow 102 through of the tube 104 in a known manner. Therefore, the velocity of these vortex disturbances is related to the velocity of the flow 102 and therefore the volumetric flow velocity can be determined, as will be described in more detail below. The volumetric flow is determined by multiplying the speed of the fluid 102 by the cross-sectional area of the tube 104. The Flow Logic 166 of the processing unit 112 processes the ultrasonic signals as shown in Fig. 11. The Flow logic 166 receives the Ultrasonic signals from the array of detectors, 124-130. A data acquisition unit 168 (e.g., an A / D converter) converts the analog signals to the respective digital signals. The digitized signals are provided to a logic 170 of Fast Fourier Transform (FFT). The FFT logic 170 calculates the Fourier transform of the time-based digitalized input signals T, (t) -TN (t) and provides signals Tx (?), T2 (?), T3 (?), TN ( ?) of complex frequency domain (or based on frequency), indicative of the frequency content of the input signals. In place of the FFT, any other technique can be used to obtain the characteristics of the frequency domain of the signals T, (t) -TN (t). For example, the cross-spectral density can be used to form frequency domain transfer functions (or the response or frequency relationships) discussed below.
A technique for determining the convective velocity of turbulent eddies 164 within process flow 102 (see Fig. 5) involves characterizing a convective peak of the resultant unstable pressures, using an array of detectors or other beamforming techniques. , similar to that described in the North American Patent Application Serial Number (CIDRA Registration Number: CC-0122A) and US Patent Application Serial Number 09 / 729,994 (CIDRA Registration Number: CC- 0297), filed on December 4, 2000, now US 6,609,069, which is incorporated herein by reference. A data accumulator 172 accumulates the signals T, (?) -TN (co) during a sampling interval, and provides the data to a processor 174 of the array, which performs a spatial-temporal (two-dimensional) transformation of the detector data, from the domain x (t) to the domain k- ?, and then calculates the power in the plane k- ?, as represented by the graph of k- ?. The array processor 174 uses algorithms called beamforming, array processing, or adaptive array processing, i.e. algorithms to process the signals of the sensors using various delays and weights to create adequate phase relationships between the signals provided by the array. the different detectors, thus creating a functional array of antennas. In other words, beamforming or array processing algorithms transform the time domain signals of the array of detectors into their spatial and temporal frequency components, that is, into a set of wave numbers given by k = 2p / ?, where ? is the wavelength of a spectral component, and the corresponding angular frequencies given by? = 2pv. The prior art teaches many algorithms to be used by spatially and temporally decomposing a signal of an array in detector phase, and the present invention is not restricted to any particular algorithm. An adaptive array processing algorithm is the Capon algorithm / method. Although the Capon method is described as a method, the present invention contemplates the use of other adaptive array processing algorithms, such as the MUSIC algorithm. The present invention recognizes that such techniques can be used to determine the flow rate, that is, that the signals caused by a stochastic parameter conveyed by convection with a flow are stationary in time and have a coherent length for a sufficient time at such time. degree that it is practical to locate the detector units separated from each other and still be within the coherent length. The characteristics or the connective parameters have a dispersion relation that can be approximated by the equation of the straight line, k =? / U where u is the velocity of convection (flow). A graph of k-pairs? obtained from a spectral analysis of samples of the detectors associated with the described convection parameters so that the energy of the spectrally corresponding perturbations to matings could be described as a substantially straight ridge, a ridge that in the theory of the turbulent boundary layer It is called a convection ridge. What is detected are not discrete events of turbulent eddies, but rather a continuum of possibly overlapping events that form a temporarily stationary process, essentially white across the range of frequencies of interest. In other words, the convection eddies 164 are distributed across a range of length scales and therefore of temporal frequencies. To calculate the power in the k- ?, plane, as represented by a graph of k-? (see Fig. 12) of, any of the signals, the processor 174 of the array determines the wavelength and thus the number of waves (spatial) k, and also the frequency (temporal) and thus the angular frequency?, of several of the spectral components of the stochastic parameter. There are several algorithms available in the public domain to carry out the spatial / temporal decomposition of the arrays of the units, 124-130, detectors. The present invention can use temporal and spatial filtering to precondition the signals to effectively filter the common mode characteristics Pm? Do common and other long wavelength characteristics (as compared to the separation of the detectors) in the tube 104 by differentiating adjacent detectors and retaining a substantial portion of the stochastic parameters associated with the flow field and other stochastic parameters of short wavelength low frequency (as compared to the separation of the detectors). In the case of the suitable turbulent eddies 164 (see Fig. 5) which are presented, the power in the k- plane? shown on a graph of k-? of Fig. 12 shows a convection ridge 176. The convection peak represents the concentration of a stochastic parameter that is transported by convection with the flow 102 and is a mathematical manifestation of the relationship between the spatial variations and the temporal variations described above. Such a graph will indicate a trend for the k-? appear more or less along a line 176 with some slope, the slope indicating the flow. Once the power in the k-? Plane is determined, an identifier 178 of convection ridges uses one or other feature extraction method to determine the location and orientation (slope) of any convection ridge 176 present in the plane. k- ?. In one modality a so-called declining stacking method is used, a method in which the accumulated frequency of k-pairs is compared. on the graph of k-? along different rays emanating from the origin, each different ray that is associated with a different test convection velocity (because it is assumed that the slope of a ray is the caudal or correlates with the caudal in a known way) . The convection peak identifier 178 provides information about the test convection velocities, information generally referred to as convection peak information. An analyzer 180 examines the information of the convection ridges that includes the orientation (slope) of the convection ridges. Assuming that the dispersion relation of the straight line is given by k =? / U, the analyzer 180 determines the velocity of the flow, the Mach number and / or the volumetric flow. The volumetric flow can be determined by multiplying the cross-sectional area of the interior of the tube 104 with the velocity of the process flow 102. The water cut of the process flow 102 can be determined using the output of at least one of the detectors, 124-130, of the ultrasonic flow meter 108. Although an ultrasonic detector, 124,130, of the ultrasonic flow meter 108 is used to determine the water cutoff of the flow 102, it is contemplated that a separate ultrasonic detector may also be used to determine the water cutoff. A separate detector for measuring water cutoff would allow the detector to transmit an ultrasonic signal at different frequencies to ensure that the ultrasonic water cutoff detector operates at a frequency greater than the resonance frequency of the bubbles. The SOS Logic of the Liquid converts the measured transit time of the ultrasonic signal to a signal indicative of the sound velocity of the liquid component of the mixture 102. The frequency of the ultrasonic signal propagating through the flow 102 of the fluid is greater than the resonance frequency of the bubbles such that the entrained gas does not affect the ultrasonic signal. By knowing the SOS of the liquid portion of the fluid flow 102, the water cutoff of the flow 102 of the fluid can be determined. The water cut is a function of the SOS of the liquid component of the mixture 102, the SOS of oil, the SOS of water, the density of oil, and the density of water. Knowing the SOS and the density of the oil and water, the relationship between the water cut of the flow 102 and the SOS of the liquid component of the mixture 102, the water cut can be determined. As shown in Fig. 13, this relationship is illustrated in the graph of the SOS of the liquid component of the mixture 102 versus the water cut of the mixture 102, and therefore, knowing the SOS of the liquid component of the mixture 102, the water cut can be determined. The water cutoff is defined as: where fw is the phase fraction of the aqueous component of the fluid flow, and f0 is the phase fraction of the oil component of the fluid flow. In addition, the phase fraction of the fluid flow can be characterized as: 1 = f "+ f0 + fg where fw is the phase fraction of the aqueous component of the fluid flow, fQ is the phase fraction of the oil component of the flow of the fluid, and fg is the phase fraction of the gaseous component of the fluid flow.
The present invention measures the water cut (Wc) and the
GVF (fg), as described below. The processor 114 using the above relationships (formulas) can determine the phase fractions of water (fw) and oil (f0) (i.e., the composition of fluid flow 102). The processor 114 can then (knowing the phase fraction of each fluid component) determine the volumetric flow rate of each component using the following formula: QP = (U) (A) Where Qp is the volumetric flow rate of the phase (component) , fp is the phase fraction of the phase; and U is the velocity of the fluid flow, and A is the cross-sectional area of the tube. Although the sonar-based flow meter 100 using a detector arrangement, 124-130, is shown and described for measuring the sound velocity of the acoustic waves 90 propagating through the mixture, it will be appreciated that it can be detected. using any means for measuring the sound velocity of the acoustic waves, to determine the volume fraction of the entrained gas of the mixture / fluid 102 or another characteristic of the flow 102 described below. Although each of the ultrasonic units 124-130 of FIG. 1 comprises a pair of detectors (transmitter and receiver), 131, 132, diametrically opposed ultrasonic to provide transmission from one side to another, the present invention contemplates that one of ultrasonic detectors,
131, 132, of each unit, 124-130, detector can be adjusted axially such that the ultrasonic signal from the transmitting detector 131 has an axial component in its propagation direction. The present invention also contemplates that the units 124-130, detectors of the detection device 112 can be configured in a pulse / echo configuration. In this embodiment, each unit, 124-130, of detection comprises an ultrasonic detector that transmits an ultrasonic signal through the wall of the tube 104 and the fluid 102 substantially orthogonal to the luxury direction and receives a reflection of the signal ultrasonic reflected back from the tube wall 104 to the ultrasonic detector. In addition, the detection device 112 can be configured to operate in a step and stop configuration. In this embodiment, each unit, 124-130, detector comprises a pair of detectors (transmitter, receiver), 131,
132, ultrasonically arranged axially along the tube to be arranged on the same side of the tube 104, at a predetermined spacing. Each transmitting detector 131 provides an ultrasonic signal at a predetermined angle within the flow 102. The ultrasonic signal propagates through the fluid 102 and bounces off the inner tube surface 105 and reflects the ultrasonic signal back through the flow 102 to the detector 132 respective receiver. As shown in Fig. 1, although the portion of the ultrasonic detector comprises an array of units, 124-130, ultrasonic detectors (see Fig. 5), the present invention contemplates that any meter or detection portion 108 may be used. of ultrasonic flow. The ultrasonic flow meter 108 can be any meter in any of the three kinds of flow meters that use ultrasonic transducers, which include ultrasonic flow time (TTUF) flow meters, ultrasonic flow meters (DUF) and meters of cross-correlation ultrasonic flow (CCUF). The portion of the ultrasonic detector may be any known ultrasonic flow meter 108, such as U.S. Patent No. 2,874,568; U.S. Patent No. 4,004,461; U.S. Patent No. 6,532,827; U.S. Patent No. 4,195,517; U.S. Patent No. 5,856,622; and U.S. Patent No. 6,397,683, which are incorporated herein by reference. The array-based flow meter 108 is similar to that described in the North American Patent Application Serial Number: 10/007, 749, filed on November 7, 2001 (Attorney's Record No. CC-066B), US Patent Application Serial Number: 10 / 007,736, filed on November 8, 2001 (Attorney's Record No. CC- 0122A), U.S. Patent No. 6,587,798, filed November 28, 2001 (Attorney's Record No. CC-0295). The Provisional Patent Application Serial Number: 60 / 359,785, filed on February 26, 2002 (Attorney's Record No. CC-0403), the Provisional Patent Application Serial Number: 60 / 425,436, filed on December 12, 2002 November 2002 (Attorney's Record No. CC-0538), the North American Patent Application Serial Number: 09 / 729,994, filed on December 4, 2000 (Attorney's Record No. 297), and the North American Patent Application with Serial Number: 10,875,857 (Attorney's Record No. CC-0749) filed on June 24, 2004, all of which are incorporated herein by reference. Although a processor 114 of the array is shown to receive and process the input signals of the detector, 116-122, of pressure and the detector, 124-130, ultrasonic, the present invention contemplates that a processor of the array can be dedicated to each one of the arrays of detectors, 116-122, of pressure and array of detectors, 124-130, ultrasonic. In addition, although the units, 142, 168, of data acquisition, logic, 144, 170, FFT, accumulators, 146, 172, data, processors, 148, 174 of the arrays and identifiers, 154, 178 of ridges, are shown as separate elements or separate logic elements / programming routines, it will be appreciated that each of these elements can be common and can process associated data with both the pressure signals associated with the speed of sound and the pressures which are transported by convection with the flow 102 of the process. FIG. 14 illustrates a block diagram of a flow measurement apparatus 200 similar to the apparatus of FIG. 1 including a sensing device (detector head) 112 mounted on a tube 104 and a processing unit or processor (FIG. transmitter) 114 of the arrangement. The apparatus functions as a GVF meter 106, a flow meter 108, and a water cut meter 110. In this embodiment, the head 112 of the detector for the GVF meter 106 functions as the head 112 of the detector for both the GVF meter 106 and the flow meter 108 of Fig. 1. The processing of all the data is similar to that described below. Similar reference numbers constitute the same elements and function in the same way as those described above. Referring to Fig. 15, the head 112 of the detector includes an array of detectors, 116-122, based on stresses or pressure. The signals provided by the pressure detectors 116-122 are processed to determine the gas volume fraction (or vacuum) of the flow 102, the flow velocity 102, the volumetric flow rate and the speed of sound of the mixture ( that is, the flow) 102. The GVF / flow meter combination, according to the present invention, could determine the speed at which the sound propagates (i.e., the acoustic waves 90 in Fig. 5) to through the flow 102 of the fluid within the tube 104 to measure the sound velocity of the mixture 102 and the empty fraction of the gas (or volume) of the flow 102. The GVF meter can also determine the rate at which the gases propagate. pressure disturbances (e.g., vortical disturbances) through the tube 104 to determine the velocity of the flow 102 of the fluid. Pressure disturbances may be in the form of vortex disturbances 164 (eg, turbulent eddies, Fig. 5) or other pressure disturbances that are transported (or propagated) by convection with flow 102. As suggested and further described in more detail below, the apparatus 200 has the ability to measure the speed of sound (SOS) and the flow rate (or velocity) using one or both techniques of the following techniques using the same array of detectors, 116-122, of pressure described here below. 1) Determining the sound velocity of the acoustic disturbances or the sound waves propagating through the flow 102 using the array of detectors, 116-122, of pressure, and / or 2) Determining the velocity of the pressure disturbances (for example, vortical vortices 164) propagating through flow 102 using the array of detectors, 116-122, of pressure. These techniques are similar to those taught and described above with reference to Figs. 8 and 11, respectively. Also, the processing relative to the measurement 110 of the water cut is similar to that described here above. One of ordinary skill in the art would appreciate that the water cut meter 110 can also be used as an individual meter to allow a user to measure the water cut of a multi-phase fluid flow 102 which entrains entrained air. The detectors, 116-122, of pressure and the detectors, 124-130 ultrasonic shown in the apparatus, 100, 200, in FIGS. 4 and 5, respectively, can be clamp detectors, not soaked. These clamping detectors allow the apparatus 100, 200 to be adapted or modified in the tubes 104 without having to stop the system. The apparatus, 100, 200, would also not interfere with the flow 102 of the fluid or create any back pressure of the flow 102 of the fluid. Another advantage of non-soaked detectors, clamped with pliers is that corrosion or scale does not interfere with the detectors. In one embodiment, as shown in FIGS. 4 and 15, each of the pressure detectors 116-122 may include a piezoelectric film attached to a unitary multiple band belt for measuring unstable pressures of the flow 102 using any technique described above. The piezoelectric film detectors 116-122 can be mounted on a unitary substrate or network, which can be mounted or secured on the external surface 132 of the tube 104, which will be described in more detail below. The detectors, 116-122, of piezoelectric film may include a piezoelectric material or film to generate an electrical signal proportional to the degree to which the material is deformed or mechanically stressed. The piezoelectric sensing element is typically shaped to allow full or almost complete circumferential measurement of the induced stresses, to provide a pressure signal averaged over the circumference. The detectors, 116-122, can be formed from PVDF films, co-polymer films, or flexible PZT detectors, similar to those described in "Piezo Film Sensors Technical Manual" provided by Measurement Specialties, Inc., which is incorporated here as a reference A piezoelectric film detector that can be used by the present invention has part number 1-1002405-0, LDT4-028K, manufactured by Measurement Specialties, Inc. Although the piezoelectric material provides substantially the length of the band, and so both the circumference of the tube 104, the present invention contemplates that the piezoelectric film material can be disposed along a portion of the band of any length less than the circumference of the tube 104. The piezoelectric film ("piezo-film"), similar To the piezoelectric material, it is a dynamic material that develops an electric charge proportional to a load on the mechanical stress. Accordingly, the piezoelectric material measures the induced stresses within the tube 04 due to unstable or stochastic pressure variations (e.g., vortical and / or acoustic) within the process flow 102. Efforts within tube 104 cause transduction to an output voltage or current or by the detector, 116-122, piezoelectric adhered. The material or piezoelectric film can be formed from a polymer, such as a polarized fluoropolymer, polyvinyl fluoride (PVDF). The piezoelectric film detectors are similar to those described in the North American Patent Application Serial Number: 10 / 712,818 (CiDRA Registry No. CC-0675), filed on November 12, 2003 and the North American Patent Application Number Series: 10 / 795,111 (CiDRA Register No. CC-0731), filed on March 4, 2004, which are incorporated herein by reference. The advantages of this clamping technique using piezoelectric film include non-intrusive, low-cost flow measurements and measurement techniques that do not require a source of excitation. It should be appreciated that the detector (s) 116-122 may be installed or mounted on the tube 104 as detectors 116-122, individual or all detectors 116-122 may be mounted as unit units as shown in the drawings. FIGs. 4 and 15. The pressure detectors 116-122 of FIG. 4 described herein can be any type of detectors capable of measuring the unstable (or ac or dynamic) pressures or the parameters conveyed by convection with the flow 102 within the tube 104, such as piezoelectric, optical, capacitive, resistive (for example, Wheatstone bridge), accelerometers (or geophones), speed measuring devices, displacement measuring device, ultrasonic devices, etc. If the optical pressure detectors are used, the detectors 116-112 may be pressure detectors based on Bragg gratings, such as those described in the North American Patent Application Serial Number: 08 / 925,598, entitled "High Sensitivity Fiber" Optic Pressure Sensor For Use In Harsh Environments, "filed on Sept. 8. of 1997, now US Patent 6,016,702, and in the US Patent Application Serial Number: 10 / 224,821, entitled "Non-Intrusive Fiber Optic Pressure Sensor for Measuring Unsteady Pressures within a Pipe", which are incorporated herein by reference . In one embodiment of the present invention using optical fibers such as pressure detectors 116-122, pressure sensors 116-122 can be individually connected or multiplexed along one or more optical fibers using multiplexing. by wavelength division (WDM), time division multiplexing (TDM), or any other optical multiplexing technique. In certain embodiments of the present invention, a piezoelectric pressure transducer can be used as one or more of the pressure detectors 116-122 and this can measure unstable (or dynamic or ac) pressure variations within the tube 104, measuring the pressure levels within 104. These detectors, 116-122, can be placed within the tube 104 to make direct contact with the process flow 102. In one embodiment of the present invention, the detectors 116-122 comprise pressure detectors manufactured by PCB Piezotronics. In a pressure detector there are integrated circuit piezoelectric mode-type detectors that present integrated microelectronic amplifiers, and convert the high impedance load into a low impedance voltage output. Specifically, a Model 106B manufactured by PCB Piezotronics, which is a piezoelectric quartz pressure detector, integrated circuit, acceleration compensation, high sensitivity suitable for measuring the low pressure acoustic phenomena in hydraulic and pneumatic systems is used. Also within the scope of the present invention is that any stress sensing technique can be used to measure variations in stresses in the tube 104, such as piezo-resistive strain gauges attached to the tube 104. Other strain gauges include resistive sheet meters having a race track configuration similar to that described in the US Patent Application Serial Number: 09/344, 094, filed June 25, 1999, now US 6,354,147, which is incorporated herein by reference. The invention also contemplates stress gauges that are arranged around a predetermined portion of the circumference of the tube 104. The axial location of and distance of the spacing? Xi,? X2 between the detectors, 116-122 of stresses are determined as described here above. The information / measurements provided by the present invention can be used to monitor the characteristics of the flow that flows with the tube, to control a process, and to diagnose problems in the process. The user also retrieves the data stored in the processor via a device / input / output ports. It is also within the scope of the present invention that any other stress detection technique can be used to measure variations in stresses in the tube 104, such as highly sensitive piezoelectric, electronic or electrical strain gauges attached to or incorporated in the tube. tube 104. Although the description has described the apparatus, 100, 200, as a unit meter that measures the GVF, the flow and the water cut, each function can be separated into individual meters to measure the GVF, the flow and the cut of water. Although the embodiments of the present invention include detectors or clamping devices with pliers, it will be appreciated that the sensors or devices may be ported or soaked to be in contact with the flow 102 of the fluid.
The present invention further contemplates that a fluid mixing device, similar to that known in the art, can be arranged before (or upstream of the flow) the detectors, to provide a well-mixed fluid. A well-mixed fluid ensures a minimum or no delay between the liquid phase and the gas phase. The delay is defined as a difference in the velocity between the liquid phase and the gas phase of the flow 102 of the fluid. The dimensions and / or geometries for any of the embodiments described herein are for illustrative purposes only and, in themselves, other dimensions and / or geometries may be used if desired, depending on application requirements, size, efficiency, manufacture or other factors, in view of the teachings here. It should be understood that, unless otherwise stated herein, any of the features, features, alternatives or modifications described in relation to a particular embodiment herein may also be applied, used or incorporated with any other modality described herein. Also, the drawings here are not drawn to scale. Although the invention has been described and illustrated with respect to the exemplary embodiments thereof, the foregoing and the various other additions and omissions may be made thereto without departing from the spirit and scope of the present invention.